I concur with steve's comment. it also applies to my 1.60 Gasser. I am only at full throttle on long up lines or when trying to hover. The plane will hover with the 1.60. Just not close to the ground because you have zero margin for error. But the 1.60 gas flies this thing fine. There is another gas engine you might look at that is light and powerful between the 1.60 mvvs and 2.15 mvvs. Thats the RCS 1.80, although I am not familiar with it.

PS: RC I should have read your whole post. the altitute thing must make flying up there interesting and it sounds like it kind of throws all the normal dynamics out the window.